From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1D0M9n-0008WD-Sx for qemu-devel@nongnu.org; Sun, 13 Feb 2005 10:59:36 -0500 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1D0M9l-0008Ut-IH for qemu-devel@nongnu.org; Sun, 13 Feb 2005 10:59:34 -0500 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1D0M9l-0008UC-3t for qemu-devel@nongnu.org; Sun, 13 Feb 2005 10:59:33 -0500 Received: from [212.16.62.51] (helo=mail.13thfloor.at) by monty-python.gnu.org with esmtp (Exim 4.34) id 1D0Lvf-0006fL-0g for qemu-devel@nongnu.org; Sun, 13 Feb 2005 10:44:59 -0500 Date: Sun, 13 Feb 2005 16:44:57 +0100 From: Herbert Poetzl Subject: Re: [Qemu-devel] Funny Bash Script ... Message-ID: <20050213154457.GA16486@mail.13thfloor.at> References: <20050213072120.GA25583@mail.13thfloor.at> <420F0871.10706@wasp.net.au> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <420F0871.10706@wasp.net.au> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Brad Campbell Cc: qemu-devel@nongnu.org On Sun, Feb 13, 2005 at 11:57:37AM +0400, Brad Campbell wrote: > Herbert Poetzl wrote: > >Hi Folks! > > > >there is a funny bash script available at > > > > http://vserver.13thfloor.at/Stuff/QEMU/rev_01.sh > > > >using this on object files (like the kqemu-mod-i386.o) > >produces interesting output, which will compile nicely > >with gcc to something very similar of the original .. > > Anyone can disassemble a binary and re-compile it. sure, that's why this script is there ... ;) > Understanding exactly how it works is another story entirely. agreed, but understanding binary code is harder ;) > I believe you would be in violation of the license if you > distributed the de-compiled source, so what do you gain by > doing this? well, I'm pretty sure that most of the current qemu hackers are able to _understand_ readable assembler code, so it might not be that complicated ... > In addition, we are talking kernel code here. yes, I'm aware of that, but let me assure you, this kernel code is much simpler than most of the userspace part qemu folks are working with/on ... > The sort of stuff where random compiler optimisations can cause > catastrophic failures. of course, and some hackers have been eaten by a grue! > Can you guarantee by doing this you are generating exactly the > same code as you started with? nobody wants to do that, otherwise you could take the object file and be done, nevertheless, comparing the disassembled code of two object files usually sheds some light on the differences (i.e. with diff) > I would certainly be loathe to trust the compiled binary. but an unknown, proprietary object file nobody takes liability for you trust ... i.c. best, Herbert > Brad > -- > "Human beings, who are almost unique in having the ability > to learn from the experience of others, are also remarkable > for their apparent disinclination to do so." -- Douglas Adams > > > _______________________________________________ > Qemu-devel mailing list > Qemu-devel@nongnu.org > http://lists.nongnu.org/mailman/listinfo/qemu-devel